1. Field of the Invention
This invention relates to apparatus for cutting stacks of flat workpieces, particularly of making undershirt-shaped bags from stacked tubular film sections made of thermoplastic material and formed with side gussets and with top and bottom end seams welds. The apparatus includes punch-and-die sets, which are mounted in a machine frame and include punches associated with drive means for moving said punches up and down, and die plates, which are fixed to the machine frame, and also including a conveyor for intermittently feeding the stacks between, and for removing them from, the punches and dies.
2. Description of the Prior Art
In general apparatus tubular film section cutting as is from Published German Application No. 29 15 689 and from Published German Application No. 33 31 069 (corresponding to U.S. patent application Ser. No. 644,280 filed Aug. 27, 1984 now U.S. Pat. No. 4,589,183 ) and is used to make undershirt-shaped bags. However the punches and dies become dull after a relatively short time so that the dull punches and dies must be reground or replaced after relatively short intervals of time, and the machine is inoperative for relatively long times.